Like Hydeous, I think it is too soon to say, but 1/4 scale articulated figures
feel like more of a fad to me. Seems that Hot Toys is only doing it as escalation to better run Enterbay into the ground, otherwise it would be an Enterbay only thing and wouldn't be getting
too much attention.
There is a pretty rich history of 1/6th scale collecting (going back to GI Joes and Barbies) in part because I think it is a size of collectible that we intuitively like and know what to do with. 1/4 scale is, like Devilof76 says, a bit clunkier for action figures, will be much more expensive, and will take up so much more space. I think they will be reasonably popular, but that they will appeal to more of a niche audience, similar to 1/4 scale statues.
That being said, I really hope HT is still doing these by the time Avengers 2 comes around. Because a larger Giant Man (1/4 scale of his normal height
) would be great.